My name is LeRoy Harbach I work for CMC Rescue
Im one of the rescue school instructors I teach in a variety of different locations
and today were here to talk about the MPD™, the operation, and how to use it. So the MPD
is designed to replace all of this traditional set-up that you would typically fined with
the anchor plate, descent control and in the particular case a bar rack, the load release,
change of direction pulley, and the prusik is all replaced by this one piece of equipment
that will effectively and efficiently do all of the same jobs thats done by this traditional
set-up. So the MPD is UL classified to the NFPA 1983 standard as a pulley, auxiliary
equipment, as well as a descent control device so it carries multiple certifications for
one piece of equipment. The MPD comes in two different sizes. You have the 11mm version
and the 13mm version. Both are designed to be used with static or low stretch kern mantle
rope. To go over how it operates and the actual components you have the release handle which
does not engage unless you lift up on it. That prevents any inadvertent bumping from
releasing the load or allowing the load to go down. The parking break is designed that
if the operator needs to walk away they can set the parking break, put it into position
and not have to be concerned if the load is going to move. You have the front cover which
has the gear drive underneath that operates the release and then the front cover plate
which has the the data and the classifications on the front. On the backside is the graphic
that show hand position as well as the load side of the MPD. Now when you look at it and
and how it operates is there is a one way bearing on the pulley shiv on the inside so
that it will only spin as a high efficiency pulley in the raising position but because
its a one way bearing it actually engages this moveable break. Now the way the moveable
break works is there is a smooth interface between the fixed friction post and the moveable
break so that will squeeze the rope or hold the rope in that position and because theres
no teeth and its not jawed its a very smooth interface where you don't have to worry about
rope damage. The secondary friction post is there as the rope as the rope would come up
and through the backside to pick up additional friction for loads that are much heavier to
be able to lower them in a controlled fashion and then the becket on the bottom is a rated
connection point for either a forward tie or to take a build a mechanical advantage.
So now were going to cover how to load the device, connect it into the anchor, do safety
check on it as well. First thing to remember is to make sure the parking break is in the
off position, turn the device over and you want to follow the graphic. I like the refer
to it as the load goes on the short side of the body as you look at it. So you rotate
the cover plate open, put the rope over the tope of the shiv, bring it down between the
fixed friction and the movable break, and close it. Its very critical that the rope
is underneath where this bent flanger the shoulder is because it keeps the rope tracking
over the top of the shiv. Where going to take it, connect it directly into our anchor, make
sure that the carabiner is locked and the give a sharp tug on the load side to make
sure that rope doesn't peel through the device it insures that its properly rigged and that
the device locks up immediately. As soon as I put tension on it the device should lock
and nothing should happen when I pull. Ok, when to use and set the parking break if the
operator would need to walk away from the device as their setting up either their doing
a change over from a raising system to a lowering system or a lowering system to a raising system
you want to set the parking break by turning it into the locked position. If I have rope
thats muddy or wet I may need to actually lift up and turn the release handle in the
clock wise position to get additional friction to be able to get it into fully locked position.
If the operator needed to walk away completely from the device and didn't have their hand
on the rope I would want to close the system by bringing the running part over the top
of the standing part of the rope and tie it off with an over hand. Its that universal
sign that the system has ben safetied off. To use the MPD as a descent control device
theres a few critical things that you really want to remember. First of all you want to
feed the rope from behind the device and your primary friction is actually at the fixed
break through the V-groove on the backside. You want to maintain that nice S shape to
the rope and when we operate the release hand we want to operate it fully open and use your
back hand as your primary friction. At no point in time should the rope angle be less
than 90º as it approaches and goes into the backside of the device. To operate it I want
to start off with my hand back in this maximum friction position, take the parking break
off, rotate the handle clockwise initially without lifting up on it then I want to lift
up on it and turn it into the maximum release position and then by letting the rope move
through your hand makes for a nice smooth descent or a nice smooth lowering operation.
If at any point in time I feel like I'm losing control of the load and I let go of the handle
the load will stop. If I fined that I don't have enough friction I can always take and
rig the rope through the secondary friction post which will give me the maximum amount
of friction during that lowering operation. To use the MPD as a belay device couple of
things you want to remember. Hand should be in a neutral position, flat and what were
trying to do is were trying to illuminate the amount of slack between your hand and
the load itself. The other key thing is that I want to stay even with or slightly ahead
of my main lowering system. The idea is to feed the rope end so that its unseated from
the top of the shiv and by keeping it unseated I can actually keep up with my main lowering
system. If something should happen however, the device will still engage and stop the
load from additional travel. ***(Insert slide text)*** Because the MPD has a high efficiency
pulley built in and also acts as a progress capture makes our change overs and building
MA (Mechanical advantage) very easy. So for a simple one-to-one MA, just by pulling on
this side of the rope I can bring my load up. In order to generate MA I need to rig
in moving pulleys and so by connecting into the prusik cord and hooking up our pulley
create a simple 3-to-1 MA stretching the system out a little bit simple 3-to-1 MA to bring
our load up. Now as the system collapses were as our hall team needs to reset just by slacking
in this side of the rope MPD will grab it hold it in place and I can go ahead and stretch
my system back out. If during my raising operation I fined that a 3-to-1 MA isn't enough I can
make a very quick change over by moving my single pulley back to the becket, locking
the carabiner, bring the bite of rope forward, take my double pulley connect that into the
prusik cord, take my bite rig one side plate close the other side plate and now I have
a 5-to-1 MA to be able to continue my raising operation. So once we successfully negotiated
the edge we can actually increase the level of safety by changing from a hand tight belay
to a shared tension system or a mirrored system but there are a couple of things we need to
remember, number 1 gota make sure that our attendant has good control of the load and
that he's in the fall line of the rope. By making that change and sharing the load between
the two ropes we actually bring our margin of safety or our levels of safety up a little
bit and its a very simple maneuver to do it would merely be changing hand position from
feeding rope in to bringing this hand back and then lifting up and opening up the break
while they continue to lower on the main line until the load is shared between the main
and the belay. So what were going to do is where going to demonstrate converting from
a hand type belay and a main line to a shared tension or a mirrored system on the lower.
So as we start to lower my hand position as I'm feeding in equal to or slightly ahead
of the rate of descent of the main line. Ok, so what were going to do is Im going to convert
to a shared system, bring my hand up, open, and by being nearby each other so that we
can actually see what each other is doing and matching the speed of the tracer threads
on the rope makes it very easy to equalize the tension on both ropes as much as possible.
When operating the MPD in a shared tension lowering system its critical that the approach
angle of the rope be back behind the device incase of a failure of either rope system
the remaining system will catch the load by the operator letting go of the handle. By
taking a single pulley we connect it into our prusik, rig the rope into it, and then
by extending the system out and when we get ready to actually start retrieving the load
we want to make sure the parking is off and so now by bringing the rope in or hauling
on them at the same rate of speed were actually trying equalize or share the load between
the two ropes at all times. For care and maintenance of the MPD its a very simple device to be
able to maintain. After every use you want to make sure that its clean, theres no debris
or dirt that actually gets in the device that may effect the operation. If there is ever
an impact load that happens to it you want to do an operational check on it and if you
notice significant damage to the device it should automatically be retired from service.
For more information about the MPD visit cmcrescue.com
